Click on the round, blue play button and then select a level to begin.
Once the game starts, you will need to use your arrow keys (or your finger on the screen) to go right or left. You have a limited amount of time to get to the finish flag (marked in green) while collecting as many stars as you can along the way. On the way, you can pick up certain power-ups or run into delaying factors, such as oil or tires. Use
On the top of the screen you'll see the amount of time you have (upper right), the number of stars you've collected this round and a help button that will show you the various symbols if you've forgotten them.